mm/hotplug: enable memory hotplug for non-lru movable pages

We had considered all of the non-lru pages as unmovable before commit
bda807d44454 ("mm: migrate: support non-lru movable page migration").
But now some of non-lru pages like zsmalloc, virtio-balloon pages also
become movable.  So we can offline such blocks by using non-lru page
migration.

This patch straightforwardly adds non-lru migration code, which means
adding non-lru related code to the functions which scan over pfn and
collect pages to be migrated and isolate them before migration.

Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 5c4f48409347d3f637796fb512ebe3fbcec2f611..7946375fe4660ab49bb82a77c9a1884c1f0fa09d 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1531,10 +1531,10 @@ int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn,
 }
 
 /*
- * Scan pfn range [start,end) to find movable/migratable pages (LRU pages
- * and hugepages). We scan pfn because it's much easier than scanning over
- * linked list. This function returns the pfn of the first found movable
- * page if it's found, otherwise 0.
+ * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
+ * non-lru movable pages and hugepages). We scan pfn because it's much
+ * easier than scanning over linked list. This function returns the pfn
+ * of the first found movable page if it's found, otherwise 0.
  */
 static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
 {
@@ -1545,6 +1545,8 @@ static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
                        page = pfn_to_page(pfn);
                        if (PageLRU(page))
                                return pfn;
+                       if (__PageMovable(page))
+                               return pfn;
                        if (PageHuge(page)) {
                                if (page_huge_active(page))
                                        return pfn;
@@ -1621,21 +1623,25 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
                if (!get_page_unless_zero(page))
                        continue;
                /*
-                * We can skip free pages. And we can only deal with pages on
-                * LRU.
+                * We can skip free pages. And we can deal with pages on
+                * LRU and non-lru movable pages.
                 */
-               ret = isolate_lru_page(page);
+               if (PageLRU(page))
+                       ret = isolate_lru_page(page);
+               else
+                       ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
                if (!ret) { /* Success */
                        put_page(page);
                        list_add_tail(&page->lru, &source);
                        move_pages--;
-                       inc_node_page_state(page, NR_ISOLATED_ANON +
-                                           page_is_file_cache(page));
+                       if (!__PageMovable(page))
+                               inc_node_page_state(page, NR_ISOLATED_ANON +
+                                                   page_is_file_cache(page));
 
                } else {
 #ifdef CONFIG_DEBUG_VM
-                       pr_alert("removing pfn %lx from LRU failed\n", pfn);
-                       dump_page(page, "failed to remove from LRU");
+                       pr_alert("failed to isolate pfn %lx\n", pfn);
+                       dump_page(page, "isolation failed");
 #endif
                        put_page(page);
                        /* Because we don't have big zone->lock. we should

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 41985aa4672d02e28c52e561172c714ced3213e6..2d34cdb70f1dffebc268e310362105e3b7d4fa9c 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7227,8 +7227,9 @@ void *__init alloc_large_system_hash(const char *tablename,
  * If @count is not zero, it is okay to include less @count unmovable pages
  *
  * PageLRU check without isolation or lru_lock could race so that
- * MIGRATE_MOVABLE block might include unmovable pages. It means you can't
- * expect this function should be exact.
+ * MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable
+ * check without lock_page also may miss some movable non-lru pages at
+ * race condition. So you can't expect this function should be exact.
  */
 bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
                         bool skip_hwpoisoned_pages)
@@ -7284,6 +7285,9 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
                if (skip_hwpoisoned_pages && PageHWPoison(page))
                        continue;
 
+               if (__PageMovable(page))
+                       continue;
+
                if (!PageLRU(page))
                        found++;
                /*